Conductor Rafael Frühbeck de Burgos' Friday performance with the National Symphony Orchestra in Washington, D.C. left musicians in tears and audiences on their feet as they offered a thunderous standing ovation. But not for the music. Rather, because of the maestro's commitment to the age old industry adage — the show must go on.

Frühbeck de Burgos, despite a progressing ailment, carried on to the best of his abilities. Although he held on to the metal rail, slumped down on the podium and sat down during the performance, Frühbeck de Burgos gathered enough strength to stand up and conduct the last few moments of Respighi's bombastic Pines of Rome.

The Spanish-born 80-year-old gent, who at one point was considered a frontrunner for the Houston Symphony music director post, was scheduled to conduct this weekend's concert run with the Houston Symphony, a program that includes Beethoven's Mass in C and Stravinsky's Pulcinella. But his pneumonia-like symptoms were busy making other plans. Doctor's orders: Frühbeck de Burgos has canceled travels to Houston.

Belfast-born Courtney Lewis, who was recently appointed assistant conductor of the New York Philharmonic beginning in the 2014-15 season, will replace Frühbeck de Burgos. This 29-year-old has risen through the classical music ranks quickly, both as a leader on stage in traditional concert settings and as the founder of a forward-thinking chamber orchestra inspired by Venezuela's El Sistema program.

Lewis' Houston debut promises to be exciting, perhaps the start of a relationship with the Houston Symphony?